This document discusses swine flu (influenza A H1N1). It begins by providing background on influenza viruses and pandemics. It then describes the 2009 H1N1 pandemic virus as a novel reassortment strain. The document outlines symptoms and transmission of H1N1, as well as laboratory diagnosis via PCR or culture of respiratory samples. Proper collection and transport of samples is emphasized for accurate testing and reporting of results within 48 hours.

1. Swine flu
Dr. Abhijeet Mane
Department of Microbiology
BVDUMC, Pune
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2. Introduction
• Influenza viruses cause significant morbidity
and mortality throughout the world
• It occurs globally with an annual attack rate
estimated at 5%–10% in adults and 20%–30%
in children.
• Worldwide, annual epidemics: 3 to 5 million
cases of severe illness, and about 250 000 to
500 000 deaths.
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3. Contd…
• Influenza viruses belong to the family
Orthomyxoviridae.
• Immunologically, there are three types of
influenza virus: Types A, B and C.
• Type A : major cause of epidemics and
pandemics
• Type B : usually causes epidemics
• Type C: causes sporadic upper respiratory
tract illness.
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4. Influenza A
• Influenza A viruses are divided into subtypes
based on two proteins on the surface of the
virus:
– Hemagglutinin (HA): 16 different subtypes
– Neuraminidase (NA): 9 different subtypes
• Occur in different combinations in a variety of
strains that infect humans, animals (equine,
swine, seals) and birds (avian).
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5. Pandemic Influenza A(H1N1) 2009
virus
• On 11 June 2009, a new strain of H1N1 influenza
was declared to have caused a global pandemic
(Stage 6) by the World Health Organization on
the basis of being widespread.
• This influenza A virus had never been identified
as a cause of infections in people before the 2009
H1N1 pandemic.
• Thought to be a reassortment of 4 known strains
endemic in humans, birds and pigs
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6. Contd…
• Transmission:
– human to human
– via coughing, sneezing or touching contaminated surfaces
and then mouth / nose
• Symptoms :
– similar to seasonal flu
– Virus can cause very severe and fatal illness in young and
healthy people, though majority recover.
– Most ICU admissions: underlying conditions like asthma,
DM, heart disease or weak immune system
• Cause of death : Respiratory failure, Secondary
bacterial pneumonia
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7. Laboratory diagnosis
• Only for inpatient, not OPD basis.
• Sample collection preferably before antiviral
treatment.
• Sample is collected under aseptic precautions.
– Nasopharyngeal swab
– Nasal swab
– Throat swab
– Combined oropharyngeal / nasopharyngeal swab
– Nasal aspirate
– ET aspirate (Intubated patient)
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8. Laboratory diagnosis (contd.)
• Swabs with synthetic tips (polyester / Dacron)
and aluminum / plastic shaft should be used
• Cotton tips and wooden shafts : NOT
RECOMMENDED
• After sample collection, place swab in 1-3ml of
Viral Transport Medium (VTM)
– VTM: inorganic salts, organic compounds,
antibiotics, CHO, etc.
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9. Swab and VTM
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10. Laboratory diagnosis (contd.)
• Labeled samples with duly filled performa
(demographics, clinical history, co-morbidities,
etc) sent to CENTRAL laboratory immediately.
• In lab, sample stored at 2-8 Degree C.
• Transported to NIV during working hours
maintaining cold chain
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11. …at NIV
• Recommended procedure is Real Time (RT)
PCR or Viral Culture
• Have a BSL-3 level lab for processing samples.
• Performs RT- PCR test for diagnosis
• Highly sensitive and specific
• Reports generated within 48 hours and
emailed as pdf to dedicated Gmail account of
CENTRAL laboratory.
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12. Additional samples which may help…
• ETT culture
• Blood culture
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13. Thank you
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